it had markings similar to the one sent to the the f-b-i says both letters will undergo more testing. both were intercepted at off-site mail screening buildings capital police say it turns out that suspicious packages investigated in the u-stoday were "not" hazardous. but at last word - a man was still being questioned. some senate office buildings were closed for a time. and senator carl levin says tests are being done on a suspicious letter sent to his michigan office. a staffer who discovered the letter is spending the night in the hospital as a precaution.but he has shown no signs of poisoning. targeted with ricin. people started asking.what ricin is a toxin or poison found in castor beans. castor beans come from castor plants like this one. the plants are popular with some gardeners. ricin comes from castor oil which is found in castor beans. in its purest form, ricin is a light colored powder. officials say it's most dangerous for people when they swallow it, inhale it, or are injected with ricin. they say it's difficult to absorb ricin thriough contact with skin. however, ricin